Principal Findings:

Prior ECV had been performed in 18% of patients. Median duration of the current episode of AF was ~60 days, and total history of AF was ~120 days.

There was no difference in the primary endpoint of permanent AF by 18 months for the comparison of acute versus routine serial cardioversion (32% vs. 31%, p = 0.85). Patients in the acute group had more ECVs (median 3 vs. 2, p < 0.05; ≥3 ECVs 54% vs. 33%, p < 0.01). There was no difference in unsuccessful ECV or subacute recurrence of AF within 30 days between groups (58% for acute vs. 56% for routine serial, p = NS).

Use of beta-blocker therapy to maintain adequate rate control was higher in the digoxin group compared with the verapamil group (60% vs. 38%, p = 0.01). Spontaneous conversion occurred more frequently in the verapamil group (12% vs. 1% for digoxin, p = 0.01). There was no difference in the primary endpoint of permanent AF by 18 months for the comparison of digoxin versus verapamil (36% vs. 28%, p = 0.33). Patients in the digoxin group had more ECVs (median 3 vs. 2, p < 0.001; ≥3 ECVs 60% vs. 28%, p < 0.001).

Interpretation:

Among patients with persistent AF, acute ECV was not associated with a difference in permanent AF by 18 months compared with routine serial ECVs; additionally, verapamil was not associated with a difference in permanent AF by 18 months compared with digoxin for rate control before ECV.

The latter strategy was based on the hypothesis that prevention of calcium overload by calcium antagonists would decrease intractability of AF by preventing remodeling processes. It is possible the lack of benefit observed with verapamil was due in part to the higher rate of beta-blocker use in the digoxin group needed for adequate rate control. As the authors point out, it is also possible that multiple episodes of AF increase remodeling, therefore interfering with the ability of calcium-lowering therapy to prevent remodeling.